1. Technical Field
This invention relates to devices and methods for hair removal, and, in particular, to the use of laser devices for inhibition of hair regrowth.
2. Background Information
The principal methods presently used for hair removal involve the use of electrolysis techniques or chemical depilatories. These techniques involve some pain, are time consuming, and demand a fair degree of expertise in their application. Normally do not guarantee a permanent effect.
Laser use in medicine is well known. For example, lasers are used in surgery for both cutting and cauterization. Lasers have been used for many years for removing tattoos under the surface of the skin. In this case a laser beam penetrates the skin and is absorbed by and destroys the ink particle. A similar procedure has been used for years to remove birth marks where the laser is matched to an absorption peak of the hemoglobin in erythrocytes in the tiny capillaries under the skin to destroy the capillaries.
The prior art of hair removal also includes attempts at removing hair with laser beams. Three such techniques are described in the following United States patents: Weissman et al., "Method for Laser Depilation," U.S. Pat. No. 4,388,924; Sutton, "Depilation Device and Method," U.S. Pat. No. 4,617,926; and Mayer, "Depilation by Means of Laser Energy," U.S. Pat. No. 3,538,919. All of these devices and methods teach the removal of hairs one hair at a time with a narrowly focused laser beam. Therefore, they are relatively inefficient and time consuming. A patent by Zaias, U.S. Pat. No. 5,059,192, issued Oct. 22, 1991, discloses a process for using a laser beam matched to the melanin found at the base of the hair follicle and papilla.
It has been known for at least 20 years in the medical profession that selective absorption of laser radiation can sometimes be enhanced by the technique of staining pathological tissues with various vital dyes. (See Goldman, U.S. Pat. No. 3,769,963.)
What is needed is a simple, harmless method for removal of and/or inhibiting growth of hair over a relatively broad area of skin.